The value of high adherence to tamoxifen in women with breast cancer: a community-based cohort study.

BACKGROUND: Low adherence to adjuvant tamoxifen is associated with worse health outcomes but little is known about the cost-effectiveness of high adherence. METHODS: We conducted an economic evaluation using data for all women with incident breast cancer between 1993 and 2000 who were subsequently prescribed tamoxifen in the Tayside region of Scotland. Patient-level, lifetime Markov models evaluated the impact of high vs low adherence to tamoxifen using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records. Direct medical costs were estimated for each patient and quality-of-life weights were assigned. Recurrence information was collected by case note review and adherence calculated from prescribing records with low adherence classed below 80%. RESULTS: A total of 354 (28%) patients had a recorded recurrence and 504 (39%) died. Four hundred and seventy-five (38%) patients had low adherence over the treatment period, which was associated with reduced time to recurrence of 52% (P<0.001). Time to other cause mortality was also reduced by 23% (P=0.055) but this was not statistically significant. For an average patient over her lifetime, low adherence was associated with a loss of 1.43 (95% CI: 1.15-1.71) discounted life years or 1.12 (95% CI: 0.91-1.34) discounted quality-adjusted life years (QALYs) and increased discounted medical costs of £5970 (95% CI: £4644-£7372). Assuming a willingness to pay threshold of £25,000 per QALY, the expected value of changing a patient from low to high adherence is £33,897 (95% CI: £28,322-£39,652). CONCLUSION: Patients with low adherence have shorter time to recurrence, increased medical costs and worse quality of life. Interventions that encourage patients to continue taking their treatment on a daily basis for the recommended 5-year period may be highly cost-effective.

Cohort study of adherence to adjuvant endocrine therapy, breast cancer recurrence and mortality.

BACKGROUND: Adjuvant endocrine therapy is recommended for women with oestrogen receptor-positive breast cancer, but many women do not take the medication as directed and they stop treatment before completing the standard 5-year duration. METHODS: This retrospective cohort study conducted between 1993 and 2008 of all women with incident breast cancer, who are residing in the Tayside region of Scotland, examined adherence to prescribed adjuvant tamoxifen or aromatase inhibitors (AIs). Survival analysis examined the effect of adherence on all-cause mortality, breast cancer death and recurrence, using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records. RESULTS: A total of 3361 women with breast cancer were followed for a median 4.47 years (interquartile range (IQR)=2.04-8.55). The median overall adherence was 90% (IQR=90-100%), but the annual adherence reduced after a longer period from diagnosis. Low adherence of <80% was associated with poorer survival (hazard ratios=1.20; 95% confidence interval=1.03-1.40, P=0.019). There was no significant difference for low adherence over the treatment period and recurrence, or breast cancer death, but patients with high annual adherence for 5 years had better outcomes than those with 3 or less. CONCLUSION: Low adherence to all adjuvant endocrine therapy for women with breast cancer, whether tamoxifen or AI, increases the risk of death.

The exponentiated generalized power series: Family of distributions: theory, properties and applications.

We propose a new generalized family of distributions called the exponentiated generalized power series (EGPS) family of distributions and study its sub-model, the exponentiated generalized logarithmic (EGL) class of distributions, in detail. The structural properties of the new model (EGPS) and its sub-model (EGL) distribution including moments, order statistics, Rényi entropy, and maximum likelihood estimates are derived. We used the method of maximum likelihood to estimate the parameters of this new family of distributions. Simulation study was carried out to examine the bias and the mean square error of the maximum likelihood estimators for each of the model's parameters. Finally, we showed real life data examples to illustrate the models' applicability, flexibility and usefulness.

Kumaraswamy log-logistic Weibull distribution: model, theory and application to lifetime and survival data.

We develop the new Kumaraswamy Log-Logistic Weibull (KLLoGW) distribution by combining the Kumaraswamy and Log-logistic Weibull distributions. This new model is flexible for modelling lifetime data. Some statistical properties including quantile function, hazard rate function, moments and conditional moments are presented. Model parameters are estimated via the method of maximum likelihood and a Monte Carlo simulation study conducted to assess the accuracy of the estimates. Finally, the model is applied to a real dataset.

Gastrostomy insertion in head and neck cancer patients: a 3 year review of insertion method and complication rates.

Patients with head and neck cancer who have resection, radiotherapy, chemoradiotherapy, or a combination of these require nutritional support to be implemented before treatment, and this may involve insertion of a prophylactic gastrostomy feeding tube. The aim of this study was to compare the use and complication rates of percutaneous endoscopic gastrostomy (PEG) and radiologically inserted gastrostomy (RIG) in these patients at a tertiary referral centre. We retrospectively reviewed gastrostomy data forms completed by nutritional support nursing staff over a recent 34-month period, which included information on method of insertion, 30-day postoperative serious and minor complications, and mortality. A total of 110 patients had prophylactic insertion of a gastrostomy (21 PEG, 89 RIG) over the study period. In the first 12 months 13 (31%) PEG feeding tubes were placed but in the last 12 months none were inserted using an endoscopic approach. Serious complications occurred with 2 (10%) PEG and 12 (13%) RIG; the most common cause was accidental removal of the tube (n=13, 12%). Minor complications of peristomal infection, leakage, or blockage of the tube occurred in 6 (5%) gastrostomies. No patients died during the study period. In recent years, and in the absence of recommended guidelines, there has been an increase in the elective insertion of RIG in patients with head and neck cancer. Serious complications for both methods of insertion in this study are comparable with similar reports. However, with RIG there is a high rate of tubes becoming dislodged with the potential for serious consequences. The most appropriate method to insert a gastrostomy tube in patients with head and neck cancer remains unclear.